57). Soon it was discovered that he had blocked arteries and had to undergo a quintuple bypass. During his recovery, after a few weeks of rerun broadcasts, the show was hosted by guests for several weeks. On his first show after recovering, Regis Philbin was his first guest; Letterman brought out all the doctors and nurses on the show who had helped him during his surgery and recovery. Despite nearly breaking out in tears during the show, Letterman seemed to find humor in his situation; while referring to one of his nurses, he said: "This woman saw me naked!" He continued to joke about the event for weeks after his return. Additionally, Letterman invited the alternative rock band Foo Fighters as musical guest. The band performed their 1997 single "Everlong" which Letterman personally requested, and Letterman introduced them as "my favorite band, playing my favorite song." During a later Foo Fighters appearance, Letterman said that Foo Fighters had been in the middle of a South American tour which they canceled to come play on his comeback episode. 2001 September 17 On September 17, 2001, David Letterman was the first major American comedy performer to return to the television airwaves after the September 11 attacks. In his opening monologue, absent the usual musical opening credits and cheering audience, an uncharacteristically serious and very emotional Letterman struggled with the reality of the attacks and the role of comedy in a post-9/11 world, saying: Letterman went on to praise Mayor Rudy Giuliani and the NYPD/FDNY in the monologue and ended the segment by saying "If you didn't believe it before, you can absolutely believe it now. New York City is the greatest city in the world." From that point on, Alan Kalter's opening narration at the very top of the show, which up until then poked fun at the city, introduces New York as "The greatest city in the world!" However, beginning in January 2013, Kalter's opening was changed to "From New York! Broadcasting across the nation and around the world!" and in early 2015, once again began to feature bizarre openings, minus the derogatory remarks about New York. Moreover, the opening shot of the credits, which at that time was a view of Battery Park and the World Trade Center, was changed to a dynamic helicopter view of the Statue of Liberty (used ever since) and an aerial shot of the Empire